Contact CR-doubly warped product submanifolds in Kenmotsu space forms.
Contact CR-submanifolds with parallel mean curvature vector of a Sasakian space form
The purpose of this paper is to study contact CR-submanifolds with nonvanishing parallel mean curvature vector immersed in a Sasakian space form. In §1 we state general formulas on contact CR-submanifolds of a Sasakian manifold, especially those of a Sasakian space form. §2 is devoted to the study of contact CR-submanifolds with nonvanishing parallel mean curvature vector and parallel f-structure in the normal bundle immersed in a Sasakian space form. Moreover, we suppose that the second fundamental...
Contact homogeneity and envelopes of Riemannian metrics.
Contact normal submanifolds and contact generic normal submanifolds in Kenmotsu manifolds.
We study contact normal submanifolds and contact generic normal in Kenmotsu manifolds and in Kenmotsu space forms. Submanifolds mentioned above with certain conditions in forms space Kenmotsu are shown that they CR-manifolds, spaces of constant curvature, locally symmetric and Einsteinnian. Also, the non-existence of totally umbilical submanifolds in a Kenmotsu space form -1 is proven under a certain condition.
Contributions to polynomial conformal tensors
Cosymplectic and α-cosymplectic Lie algebras
Courbure scalaire et trous noirs
CR-structures on the translated sphere bundle.
CR-submanifolds of a Lorentzian para-Sasakian manifold.
CR-submanifolds of a nearly trans-Sasakian manifold.
CR-warped product submanifolds of nearly Kaehler manifolds.
Curvature conditions on hypersurfaces with two distinct principal curvatures
We investigate curvature properties of hypersurfaces in semi-Riemannian spaces of constant curvature with the minimal polynomial of the second fundamental tensor of second degree. We present suitable examples of hypersurfaces.
Curvature operators: pinching estimates and geometric examples
Curvature properties of a semi-symmetric metric connection on S-manifolds
In this study, S-manifolds endowed with a semi-symmetric metric connection naturally related with the S-structure are considered and some curvature properties of such a connection are given. In particular, the conditions of semi-symmetry, Ricci semi-symmetry and Ricci-projective semi-symmetry of this semi-symmetric metric connection are investigated.
Curvature properties of -natural contact metric structures on unit tangent sphere bundles.
Curvature properties of φ-null Osserman Lorentzian S-manifolds
We expound some results about the relationships between the Jacobi operators with respect to null vectors on a Lorentzian S-manifold and the Jacobi operators with respect to particular spacelike unit vectors. We study the number of the eigenvalues of such operators on Lorentzian S-manifolds satisfying the φ-null Osserman condition, under suitable assumptions on the dimension of the manifold. Then, we provide in full generality a new curvature characterization for Lorentzian S-manifolds and we use...
Curvature tensors and Ricci solitons with respect to Zamkovoy connection in anti-invariant submanifolds of trans-Sasakian manifold
The present paper deals with the study of some properties of anti-invariant submanifolds of trans-Sasakian manifold with respect to a new non-metric affine connection called Zamkovoy connection. The nature of Ricci flat, concircularly flat, -projectively flat, -projectively flat, --projectively flat, pseudo projectively flat and -pseudo projectively flat anti-invariant submanifolds of trans-Sasakian manifold admitting Zamkovoy connection are discussed. Moreover, Ricci solitons on Ricci flat,...
Curvature tensors on -Einstein Sasakian manifolds.
Curvature-decreasing maps are volume-decreasing. On joint work with G. Besson and G. Courtois.